Introduction: Invasion and metastasis of malignant tumours severely endanger the life of cancer patients. Squamous cell carcinoma is one of the commonly found malignancies in the oral cavity and its survival rate has not improved from past few decades. Since an important risk factor for oral squamous cell carcinoma is the presence of epithelial dysplasia, it is necessary to check the presence of a prognosticator marker in both of them. As matrix metalloproteinaseís (MMPís) are involved in degradation of type IV collagen, which are one of the important components of extracellular matrix components which play a relevant role in several steps of tumour progression such as invasion and metastasis. We have studied MMP-9 expression to evaluate its prognostic potential in oral cancers as well as oral epithelial dysplasia along with tissues of normal oral epithelium.

Materials and Methods: The expression was examined using immunohistochemistry procedure with MMP-9 in 100 samples including cases of epithelium from normal oral mucosa, oral dysplastic lesions and oral squamous cell carcinoma. One set of formalin fixed, paraffin embedded sections of the three categories were stained by haematoxylin and eosin. The sections were then evaluated under microscope. Data was examined for statistical significance using SPSS 13.0 by Mann-Whitney Test and Kruskal-Wallis Test.

Results: With MMP-9 gain of expression was noted from Control group to oral squamous cell carcinoma. Cytoplasmic staining was seen with MMP-9. Statistically highly significant differences were seen between oral epithelial dysplasia and oral squamous cell carcinoma and statistically significant differences were found between the control group and the oral squamous cell carcinoma group.

Conclusion: This study suggested that oral squamous cell carcinoma shows higher MMP-9 expression as compared to oral epithelial dysplasia followed by epithelium from normal oral mucosa. However, no correlation was found among the histological grades of oral squamous cell carcinoma.